On The List
by acertainzest
Summary: Kate Beckett's relationship with FBI Agent Will Sorenson is fine. Just fine. Really. And investigating a murder case that involves her favorite author isn't going to change anything. Or is it? ;)
1. Chapter 1

"Morning," Kate Beckett said as she entered her boyfriend's kitchen, freshly showered.

"Good morning," Will Sorenson replied cheerfully, handing her a cup. "Coffee."

"Thanks." She flashed him a quick smile, running a hand through her still-damp hair. She had forgotten that Will didn't own a hair dryer, of course. At least she'd had the foresight to pack a change of clothes, so she wouldn't have to run back home before heading to work at the precinct.

"And breakfast," Will added proudly, leaning in for a quick kiss before gesturing her toward the kitchen table. Her eyebrows went up.

"You cooked?"

"Well, sure. A person's gotta eat," he shrugged, shuffling his feet with a bashful smile. Kate surveyed the plates he had set out: toast, bacon, scrambled eggs, orange juice, and half a grapefruit for each of them.

"Looks good," she made herself say, and forced a smile. She sipped the coffee - black and bitter, just the way she didn't like it - and moved past Will to find the vanilla creamer that she kept in his fridge. Having doctored the coffee to her liking, she took another, longer sip, sighed, and mustered up a more genuine smile for her boyfriend.

"You didn't have to do all this."

"I know," he shrugged again, moving to pull out her chair for her. "I wanted to."

Kate sat down and picked up her fork, keeping her expression neutral. It was all so very domestic, wasn't it? She wondered what had prompted all of this. It wasn't like she had never spent the night at Will's apartment before. Well, okay, this was only the third or fourth time, but...

"Do you wanna get lunch?" he asked, breaking into her muddled thoughts. She swallowed a bit of bacon and raised her eyebrows inquiringly at him.

"What, in the middle of breakfast?" she joked weakly. But Will simply shook his head, earnest as ever.

"Later today. At lunchtime," he clarified unnecessarily. "If you don't catch a murder case, I mean. I thought we could meet up at that burger place you keep mentioning? Rory's, is it?"

"Remy's," she corrected, and added after a beat, "Sure. That sounds nice."

* * *

It was a quiet morning at the 12th Precinct. By eleven o'clock, when Beckett's friend and favorite medical examiner stopped by to say hello, piles of paperwork had overtaken all of the detectives' desks, almost burying the collection of used coffee cups they were amassing.

"Hey, Lanie," Kate greeted her friend, grateful for the interruption. "You come by for a cup of our coffee?"

"Please," Lanie scoffed, tossing her head as she plopped down onto the chair beside Beckett's desk. "The coffee here is even worse than the stuff we got down at the morgue, and that's something I never thought I'd say." As Kate chuckled, Lanie added, "No, I just thought I'd pop in and see if you were free for lunch. We haven't gone out in a while."

"Oh, I would love to," Kate said regretfully, "but I already have plans with Will."

"Really." Lanie regarded her with narrowed eyes. "Could you possibly say that with any _less_ enthusiasm?"

"Ugh." Kate huffed sharply. "Lanie, don't start, okay? Everything's fine."

"Break room. Now." Lanie stood up, folded her arms across her chest, and glared until Kate gave in. Biting her lower lip, Beckett got up and followed her friend to the relative privacy of the precinct kitchen.

"Now," said Lanie after closing the door behind them. "What's going on with you and Will?"

"Nothing." Kate sighed, slumping down onto the small sofa. "I don't know. It's fine."

"The sex is good?" Lanie prompted. "Even though he isn't into any of that kinky stuff you like?"

"Lanie!" Kate scolded, instinctively looking around, although she knew no one could overhear them with the door closed. "The sex is fine, okay? He's perfectly nice. I enjoy being with him. I even spent the night at his place last night, and he made breakfast this morning and everything."

"How domestic," Lanie commented with a smirk. "But?"

"But nothing. It's all fine with us. Really."

"You're saying _fine_ way too much, girl," Lanie declared. "You wanna know what I think?"

"I already do," Kate snipped out. "You think he's boring."

"You gonna deny it?" Lanie snarked right back at her, and Kate dropped her eyes again. No, she couldn't deny it, but she just wished her friend wouldn't _say_ it so baldly. Will was a good guy, even if he was fairly... well... bland.

"But it's not just that," her friend continued. "Girl, I've seen you do this before, and you know it. You chose Will _because_ he's boring. Boring and safe, so you don't have to fully commit yourself to the relationship - so you aren't taking any chances. It's what you keep doing, ending up with these boring men you don't even really like. And then as soon as they start getting serious, you bail."

Kate could only bite her lip and stare at her hands in her lap. Her friend's words stung, and she knew - damn it - that it was because they had the ring of truth.

"I'm just not - I'm not good at relationships," she said quietly. Lanie leaned over and put a gentle hand over Kate's on her knee.

"I know, honey. But that's never gonna change if you keep hiding behind these boring men. You gotta put yourself out there, take a risk of getting your heart broken, or you're never gonna find the right guy. The guy you really deserve."

"I'm not even sure that guy exists."

"Don't be like that," Lanie exclaimed. "He's out there, Kate. You just gotta be looking for him, not another Captain America." She paused, and her lips twisted into another smirk. "You also deserve some great sex, girlfriend. You shouldn't have to settle."

"Lanie!" Kate huffed. "This conversation is over." She stood up and moved to the coffee machine. "I am not discussing sex with you at work."

"Okay, fine," her friend grinned, "but you're not off the hook. You go have lunch with Mister Boring, and we'll have dinner and drinks sometime soon. Yes?"

"Yes," Kate agreed, and gave Lanie a hug. "Thanks for the pep talk," she added grudgingly, with an exaggerated eye-roll for effect. Lanie laughed loudly as she sashayed out the door.

"Later, girlfriend!"

* * *

A few minutes after noon, Kate entered Remy's and found Will already waiting for her.

"Hey," she greeted.

"Hey," he replied with a big smile, rising from the booth to kiss her in greeting. She felt her stomach twist uncomfortably at the sight of how pleased he was to see her. Shouldn't she feel the same way about the man she was dating?

"I thought I had the wrong place for a minute," he said as they took their seats across from each other in the small booth. "It just doesn't look like your kind of restaurant."

Kate paused, wondering what that meant and whether she should be offended. "Well, almost everyone from the precinct comes here," she replied after a moment, keeping her tone neutral. "The burgers and milkshakes are fantastic."

Will's eyebrows went up, but he didn't comment.

After they had ordered their burgers - Will's with a soda, Kate's with a milkshake - he leaned forward slightly, his eyes alight with excitement.

"I'm on the short-list for a new position that just opened up," he announced. "It's not exactly a promotion, but it's a really great opportunity. I heard there are only a handful of agents being considered for it."

"That's great," Kate said sincerely. "Congratulations. When will you find out?"

"Within a week, they said, but sometimes they drag their heels on this stuff." He shrugged, clearly trying to look unconcerned. "Not much to do but wait and see."

"I'll keep my fingers crossed."

"Thanks."

There was a pause then, as the server arrived with their food, and they turned their attention to the application of ketchup and so forth.

"It was lucky, wasn't it," Will said, after they had each taken a few bites, "the way things turned out?"

"What do you mean?" Kate asked, bemused.

"Well, after we worked that kidnapping case together and, uh, hooked up," he grinned and blushed a little, "we had agreed that a long-distance relationship wouldn't work out, but just then I got the word that the Bureau wanted me to stay here in New York."

"Right." She took another bite of her burger, mulling over those memories and wondering why he had brought that up just now. "That was good timing."

"Six months ago this week," Will added, still smiling, a little timidly. "I'm just saying, I'm glad it worked out that way."

Kate focused on her food, trying to cover up the anxiety that the conversation was producing. The way Will was talking, the reference to how long they had been together - it made her nervous. He was starting to sound like he wanted to get more serious about the relationship, and she wasn't sure how she felt about that.

 _As soon as they start getting serious, you bail_ , she remembered Lanie saying just a short while ago, and she had to swallow around a lump of shame that gathered in her suddenly dry throat.

"Me too," she forced out, because she knew that was what Will was waiting for her to say. Sure enough, as soon as the words were out, his face relaxed into a smile of relief and pleasure.

Kate felt her shoulder muscles tense up, wondering where he would go next with this line of conversation; but before he got the chance, her cell phone chimed. Will frowned slightly as she pulled it out of her purse.

"It's Captain Montgomery," she said apologetically, and swiped to answer the call. "Beckett."

"Detective," said her boss's voice through the phone. "Is Sorenson with you?"

"Um," Beckett said, blushing slightly. It wasn't as if her relationship with Will was a secret, but she had tried to keep it discreet. "Uh, yes, sir," she admitted.

Montgomery, of course, didn't comment on her personal life. "We've got a new case," he said, "and the Feds are involved. They want you and Sorenson to collaborate on this one. You should both get over there right away."

"Okay," she said, surprised. She found a pen in her purse and jotted down the address that Montgomery reeled off. Just as she was hanging up, Will's phone began to ring. Beckett signaled the waitress for the bill.

"Looks like we're going to be working together again," she commented when Will ended his call, which had mostly consisted of him saying _Yes sir_.

"So it seems," he agreed, pulling out his wallet. "Shall we?"

* * *

"Who's our vic?" Beckett asked her junior detectives twenty minutes later, as she and Sorenson stepped off the elevator at the eighteenth floor of an upscale apartment building. The cab ride over had been quiet, Sorenson spending most of it with his ear glued to his phone, while Beckett gazed out the window. Will liked to talk to his team in advance, to know what he was going to find at a crime scene; Kate, on the other hand, preferred to start by viewing the scene to form her first impressions.

"Alison Tisdale," replied Esposito, glancing at his notes. "24, grad student at NYU. Part of the social work program."

"Nice place for a social worker," Beckett observed as they entered the apartment.

"Daddy's money," Ryan replied, directing her which way to go with a gesture.

"The victim was a federal informant," Sorenson added, falling into step with Beckett and her team as they proceeded toward the crime scene. "She was due to testify in federal court next week as part of a big crime-ring bust."

"Sounds like a potential motive," Ryan commented, exchanging a glance with Esposito. Beckett didn't comment. She preferred not to speculate before seeing the body.

They passed through an arched doorway and into an open room, already swarming with CSU and other officers.

"Neighbors called the super to complain about the music," Esposito supplied as they emerged into full view of the victim.

Beckett stopped short, blinking, her mouth falling open slightly as she took in the sight of the dead woman's body.

Alison Tisdale was laid out on a table, arms by her sides, her body covered with red rose petals, stark against the pale backdrop of her lifeless skin. Two bright yellow sunflowers covered her eyes.

Sorenson was saying something about Tisdale's federal contacts and a meeting to discuss her testimony, but Beckett was only half listening as she circled the body, her forehead creased. With each step, the longer she looked at the dead woman, she grew more and more certain of her first instinct. She _knew_ this scene.

"Dr. Parish, hello," Will said then, and Kate pulled her attention away from the corpse to greet her friend.

"Hey Lanie. What can you tell us?" she asked, firmly ignoring the significant glances that Lanie was directing between her and Will.

"She's got two shots to the chest, small caliber," Lanie replied, giving Kate one more narrow-eyed glare before dropping back into professional mode. She reached out with a gloved hand to move the flower petals aside so that Kate and Will could get a look at the fatal wounds.

Beckett pursed her lips and folded her arms, walking another slow circle around the body. Her junior detectives and her boyfriend - Agent Sorenson, that is - watched in silence.

"Does this look familiar to anyone else?" she asked at last, but received only blank looks in reply.

* * *

A few hours later, after a frustrating afternoon spent wrangling with federal bureaucracy and chasing down useless leads, Beckett was behind the wheel of a police cruiser with Sorenson beside her and Ryan and Esposito in the back seat.

"I'm still not sure what you hope to accomplish with this," Will complained as she steered through Manhattan rush-hour traffic. "Even if you're right about the similarity to the book-"

"I am right," she snapped, "and it's not just a similarity. It's an exact replica. I'm telling you, Will. If you had read the book, you'd have recognized it too."

"Don't start with that again," he sighed, and she bristled. But she forced herself to take a deep breath and bite her tongue. No good could come from this argument, especially not in front of her fellow detectives.

"It doesn't matter," she said after a moment, when she was sure she could trust her voice to remain even and calm. "We'll talk to him and see where it takes us."

When they stepped out of the car at the ritzy hotel where the book-release party was being held, Sorenson immediately took charge. "FBI," he informed the security guard at the door, holding up his badge. Beckett pursed her lips and refrained from comment as they were whisked inside and shown to an elevator.

Will stepped out in front again at the penthouse floor, but after bulling his way into the party, he deferred to Kate with a grimace and a nod. Technically, the FBI had no jurisdiction over the murder investigation, and everything had to be done by the book.

"Mr. Castle?" Beckett asked crisply, addressing a broad, well-tailored back. She caught a glimpse of the young redhead behind him, blue eyes widening in surprise, just before the man himself spun around, a pen held high.

"Where would you like it?" he asked, grinning.

The last time Kate Beckett had seen Richard Castle, at a book signing many years ago, he had been wearing jeans and a t-shirt, clean-shaven; tonight he was in an expensive suit and his cheeks were scruffy with the day's growth. But the effect was the same. Goosebumps tingled up and down her spine, and her guts twisted dizzyingly.

God, the man was hot.

But she was here to do her job, not to ogle. She held up her police badge and hardened her face and voice.

"Detective Kate Beckett, NYPD, and Agent Will Sorenson, FBI. We need to talk to you about a murder that took place earlier today."

For a long beat, Richard Castle simply stared at her, astonished. The redhead leaned up to whisper something in his ear, taking the pen from his fingers. Beckett's mouth was dry, watching him watch her, waiting for her words to sink in.

"Come on, buddy, let's get it moving," Sorenson rapped out, breaking the spell. Beckett cleared her throat, clipping her badge back onto her waistband. Castle blinked, his throat working as he nodded.

"Yeah. Yes. Sure thing, of course, always glad to help New York's Finest," he stammered, regaining his aplomb by the end of the sentence. "And it certainly was nice of them to send their _finest_ for me," he added, casting his gaze down Beckett's figure and back up again, his smirk reappearing. She took a deep breath, firmly shoving down the fluttering in her belly.

"Shut up," Sorenson barked, bristling, imposing his body between Beckett and Castle. "Come on." He took the other man's arm and pushed him toward the exit, using more force than necessary.

"Will," Beckett chided. He shot her a glare over his shoulder. She glared back, but to no avail - he had already turned away. Damn him.

* * *

Beckett and her team reconvened outside the door to the interrogation room. "The Fisk file," said Ryan, handing it over.

"Thanks," Beckett said, glancing through the pages summarizing an earlier murder that they had almost been ready to relegate to the cold-case pile. "Can't believe I didn't see that connection before." She shook her head, frowning.

"Hey, but you caught it now though," Ryan said, and she gave him a tight smile, acknowledging the attempt, if nothing else.

"Yo," Esposito put in, "you gonna tag-team it with Mister Feebie, or what? He looks too grumpy for a good-cop-bad-cop routine. I mean, unless _you're_ gonna play the good cop," he added in a tone of extreme skepticism. Beckett let that go with just a slight head-shake and eye-roll.

"Yeah, he's going to sit in. You boys can watch from observation. Maybe you'll learn something," she added, quirking an eyebrow. They both groaned in faux-injury, clutching their chests.

"Something funny?" Sorenson asked, approaching with his own handful of file folders and paperwork. Beckett turned to face him coolly as the others moved off toward the observation room.

"Nope. You ready?"

"Kate..." Sorenson cocked his head, studying her. "Are you sure you can do this?"

She gritted her teeth against a surge of irritation. "Are you questioning my ability to do my job?"

"No! No, of course not," he denied, lifting his free hand in a gesture of surrender. "I'm just saying..." He lowered his hand and his voice, glancing around quickly. "He is your favorite author, after all."

"Not tonight," she said decisively, slapping the folder shut in her hands. "Tonight, he's a person of interest in a murder investigation. That's all."

* * *

 _AN: Thanks for reading! This story will be six chapters, posted every 2-3 days._

 _Credit goes to LordOfKavaka for the lovely cover art; to Meg Moore for brainstorming/outlining/plotting assistance; and to ipreferwestside for betaing. Thank you all!_

 _As you may know, this site has been having some issues with uploading and posting recently. I'll be cross-posting this story on AO3 so you can find it there if ffnet decides to start being cranky again._


	2. Chapter 2

"Mr. Castle," Beckett said, drawing the eye of the author, who was comfortably seated in his chair, his jacket removed. The top few buttons of his shirt were open, but she refused to let her eyes be drawn to that tantalizing slice of skin. He gazed up at her curiously as she entered the interrogation room with Sorenson on her heels.

"You've got quite a rap sheet for a best-selling author," she commented, opening the folder again and casting her eyes across it, even though she had already committed the pertinent details to memory. "Disorderly conduct, resisting arrest..."

"Boys will be boys," Castle offered, shrugging, affecting a cherubic expression. But his attention was drawn to Sorenson, reading the file over Beckett's shoulder, and Castle's eyes narrowed. "Well, maybe not all boys, am I right?" he added, casting Beckett a conspiratorial glance, rolling his eyes toward Sorenson.

Beckett ignored that. "Do you-"

"Says here that you stole a police horse," Sorenson exclaimed, reaching around Beckett to take hold of the file.

"Borrowed," the author corrected, as Beckett scowled in Sorenson's direction. She wasn't going to call him out in front of an interview subject, but she _hated_ being interrupted.

"And you were nude at the time?" Sorenson went on, sounding scandalized.

"It was spring," Castle shrugged, smirking. Beckett had to bite the inside of her cheek to keep her expression blank, especially when she caught the tiny noise of astonished outrage that Will let out.

"And every time, the charges were dropped," she said coolly, cutting effortlessly through both Will's discomfiture and Castle's enjoyment of same. The writer immediately refocused his smirk on her, while she could still sense Will seething behind her. She slid into the chair opposite Castle, keeping her gaze firmly on him, her face betraying nothing.

"The mayor's a fan," he explained offhandedly, leaning forward. "But if it makes you feel any better, I'd be happy to let you spank me."

Beckett had only the briefest moment to experience the twisting flutter of arousal that the words created in the pit of her stomach before Sorenson was surging forward, halfway across the table with a growl of anger.

"You smug son-of-a-"

"Back off!" she snapped, her arm shooting up, slapping the back of her hand against Will's chest. She held him back with the press of her arm, her eyes never leaving Castle's face. The writer had flinched backward at Sorenson's outburst, but now he froze, eyes wide, watching her.

"Agent Sorenson, back the hell off," she said, keeping her voice low and controlled, vibrating with menace. She saw Castle shiver ever so slightly. Will's body was tense against her arm, but he gave in and took a step backward, still radiating anger that she could feel crackling in the air.

Beckett leaned forward over the table again, beckoning Castle toward her. She knew that he had tried leaning in as an intimidation technique, but she would be the one doing the intimidating in this room, damn it.

"Mister Castle," she said, still in her quiet but dangerous tone, as he submitted to the crook of her finger and leaned closer. "This whole bad-boy charm thing you've got going might work on bimbettes and celebutantes, but here in this room, you have one choice to make: you can be the guy who makes my life easier, or the guy who makes my life harder. And trust me, you do _not_ want to be the guy who makes my life harder."

She watched with carefully concealed interest as Castle swallowed, his eyes wide and fixated on her. "'Kay," he murmured in acquiescence, and she allowed the intensity of her expression to drop down a notch.

"Alison Tisdale," she said, pulling a glossy photo from her file folder and putting it down on the table. "Daughter of real estate mogul Jonathan Tisdale."

"She's cute," Castle commented, studying the picture.

"She's dead. You ever meet her? Book signing, charity event?"

"It's possible," he mused, his lips curving upward in that cocky smirk again. "She's not in my little black book, if that's what you're asking."

From behind Beckett, Sorenson gave a huff of disgust, startling both Beckett and Castle. Somewhat guiltily, Beckett realized that for a moment she had almost completely forgotten he was there.

"Try this one," Will said gruffly, moving forward to slap down a photo of his own.

"Marco di Solesino," Castle said, sounding surprised. "Oldest son of the head of the Solesino mob family."

"Ah," Sorenson exclaimed. "So, you know him."

"I know _of_ him," Castle corrected. "I'm a crime writer, so of course I'm familiar with the major players in the organized-crime world. But I've never met him."

"What about this guy?" Beckett cut in, pulling out another photo. "Marvin Fisk, small-claims lawyer."

"Most of my claims tend to be on the, um, large side," Castle replied, his expression full of mischief. Beckett rolled her eyes. "So what's this got to do with me?" he added.

Beckett took out the crime scene photos. "Fisk was killed two weeks ago, but I didn't put it together until we saw the Tisdale crime scene tonight." She showed Castle the picture of Alison Tisdale's dead body, and watched him blanch, his cocky demeanor slipping as he took in the image.

" _Flowers For Your Grave_ ," he murmured, staring at the photo.

"And this is how we found Fisk," Beckett added, showing him the next picture. "Straight out of _Hell Hath No Fury_."

Castle's forehead furrowed. "And what about Solesino?"

"What?" she said, jolted out of her rhythm by the question.

Castle looked over at Sorenson, who was still glowering in the corner of the room. "How was Solesino killed?"

"He wasn't," Sorenson replied. "He's a... person of interest in the investigation."

"Oh." Castle returned his gaze to the two photos, then looked back up at Beckett. "Well, it looks like I have a fan."

"Yeah," she agreed, "a really deranged fan."

"Oh, you don't look deranged to me," he shot back, his grin beginning to reappear. " _Hell Hath No Fury_? Come on, only hardcore Castle groupies read that one."

Sorenson let out a snort at that. Beckett narrowed her eyes, but she wouldn't give him the satisfaction of turning to glare at him. She kept her focus on Castle.

"Do any of these groupies ever write you letters?" At his nod, she went on, "Because sometimes in cases like these we find that the-"

"-killer attempts to contact the subject of his obsession," Castle interrupted, finishing her sentence for her. "I'm pretty well-versed in psychopathic methodologies." He leaned closer again, intent on her face. "And do you know you have gorgeous eyes?"

"Hey! Watch it," Sorenson snapped. Beckett bit down another surge of irritation and swept all of the photos back into their folder.

"So, I take it you won't object to us going through your mail," she said in her no-nonsense, brooking no argument tone.

"Sure, knock yourself out," Castle answered. His attention was on Will again, the two of them locking eyes across the room. Beckett rolled her eyes again and stood up.

"I think we're done here."

* * *

After Castle had left, Beckett took a few minutes to update her murder board. It was late, far past time to go home, but she needed to get all of the case information organized before she'd be able to let it go for the night.

Will stood beside her desk and watched without comment as she wrote down what little they knew so far about Alison Tisdale's final day of life.

"You really think there's a connection with Castle?" he asked when she picked up a magnet to attach Castle's photo to a corner of the board. "Kate, the victim was about to give testimony that could put Solesino behind bars for the rest of his life. That's gotta be why she was killed."

Beckett turned to face him, crossing her arms over her chest. "We'll look into that angle too," she said, "but yes, I do think there's something to the Castle connection. It can't be a coincidence that we have two murders staged to look like scenes from his books."

Will pursed his lips. "Well, Fisk had no involvement in the Solesino case, so that's not the connection. Do you really expect to find anything in Castle's fan mail?"

"I don't have expectations. I follow the evidence where it leads me."

"It's because of him, isn't it?" Will leaned closer and lowered his voice. "Because he's on the list."

Beckett stared at him blankly. She had no idea what he was talking about. "What list?"

"You know." He spoke even more quietly, glancing around to make sure no one was nearby. "Your freebie five list. The celebrities you'd want to... you know."

"That dumb thing?" Kate huffed in disbelief. "What does that have to do with anything?" She felt her cheeks flushing and cursed herself for the reaction. What had ever possessed her to confess to Will just how attractive she found the playboy writer? It had been a silly 'getting to know you' conversation early in their relationship, and if she'd had any idea that one day she would be hauling Castle in for questioning on a case...

"I'm just saying," Will shrugged. "You put him on your list, which obviously means you're interested in him, and now here he is, in the middle of things."

Beckett studied her boyfriend, her eyebrows rising as his meaning slowly sank in. "Wait a minute," she said dangerously. "Are you seriously implying that I would let my hormones dictate the course of a murder investigation?"

"No! No, no. Of course not," Will said, quickly backpedaling, lifting both hands in a submissive gesture. "I just don't think you're going to find Tisdale's killer that way. That's all."

She took a slow breath and forced her jaw muscles to relax. "It's late," she said, keeping her tone even. "Time to go home. We'll pick up the investigation in the morning."

"Okay." Will looked at his watch. "Uh... well, goodnight then."

"Night," she replied.

Beckett turned back to her desk and began to shut down her computer. In her peripheral vision she could see Sorenson still standing there, looking at her, shuffling his feet indecisively. But he didn't say anything, and after a moment he turned and walked away.

* * *

Beckett picked up some takeout on her way home, and settled in on her couch with a sigh of relief. Will's apartment was perfectly nice, but she preferred her own space.

After she had eaten, she ran a hot bubble bath and sank gratefully into it, letting the hot water soothe her tense muscles and frazzled nerves.

She let her mind wander as she lay in the tub, drifting freely. She had long ago given up on the idea of "leaving work at work," and in fact she often found that a relaxing bath or even a long shower could shake loose new ideas about a case she was working on. Some of her best investigative breakthroughs had started out that way.

So she didn't try to stop her mind from looping around the details of Marvin Fisk's and Alison Tisdale's murders as she lay there, surrounded by bubbles in the quiet bathroom.

But very quickly, without her conscious volition, her thoughts turned to Castle. She tried to push him away, wrenching her brain back to the CSU report on Fisk, but Castle just kept intruding. His rough-stubbled chin, the naughty twinkle in his eye when he had invited her to spank him... try as she might, she couldn't seem to shake him.

Damn it, this was all Sorenson's fault, she thought irrationally; he had to go and bring up the stupid Freebie Five thing. She hadn't even been thinking about that, had entirely forgotten about it until he mentioned it.

Of course, it was still true that she found Castle attractive. Who wouldn't? But that didn't mean anything. Damn it.

The calm of her bath shattered by these ruminations, she sat up, grumbling, and pulled the plug. She muttered grouchily under her breath the whole time she was drying off and getting ready for bed. At last she slid between the sheets, forced Castle out of her mind one last time, and fell asleep.

* * *

Beckett awoke with the unsettling feeling that she had been dreaming about things she shouldn't have. But she didn't remember any of the dreams, so she shook it off.

After getting dressed, she went to her living room and stood in front of her bookshelves, glaring at her Castle books. She had a sneaking suspicion that the man pictured on their back covers was going to make her day very irritating.

With a sigh, she found a box and packed all of the books into it. Then she strapped on her gun and went to work.

At the precinct, she dumped Castle's books on Ryan and Esposito, resolutely putting up with their teasing about it. Her sense of impending doom only intensified when she discovered that Castle's fan mail had arrived at the precinct with an accompaniment: the man himself. Captain Montgomery confirmed her suspicions by telling her that Castle had offered to "help" with the investigation.

Will Sorenson arrived just in time to hear Castle saying "It's the least I can do for the city I love," in a saintly tone that made Beckett want to gag. Montgomery made it quite clear that the arrangement met with his approval, and refused Beckett's attempt to change his mind.

"Captain Montgomery, with all due respect," Sorenson said with a scowl, "this investigation is no place for an amateur."

Montgomery was unmoved. "Agent Sorenson, with all due respect," he said, deliberately echoing Will's phrasing, "my team is involving you in this investigation as a courtesy, so you're in no position to tell us how to conduct it."

Sorenson paused with his mouth halfway open, but he thought better of whatever he'd been about to say, and simply nodded acceptance, pressing his lips together in a thin line.

"Right then," Montgomery said, sweeping his gaze over all of them. "Get to it."

He went back into his office, and Will immediately turned to Kate, holding up a file folder. "Solesino has an alibi," he said. "We should check it, but it'll probably hold up - he usually has someone else do the dirty work for him. We've got names on a few of his flunkies, so we should run them down and check their alibis too."

"Any of them have an M.O. that involves covering the body with flowers?" Beckett asked. Sorenson gave her a blank look.

"Sorry?" he asked.

She sighed. "Never mind. Hey, Ryan, you were in Organized Crime, right?" At the detective's nod, she said, "So you can help Agent Sorenson with his list."

Ryan took a look at her expression and decided against voicing any objection. "Sure," he said grudgingly.

Beckett felt fairly reluctant about it herself, but she knew from experience that giving the Feds at least some input into the investigation would make it all go more smoothly. And she did want to appear conciliatory toward Sorenson, for several reasons, of course.

"Espo," she went on, "keep trying to find a connection between Tisdale and Fisk. Castle and I will look through the fan mail."

"Right."

As the detectives and agent moved away to get started, Beckett turned to Castle, forcing herself to sound polite and professional. "If you'll follow me to the briefing room, Mr. Castle, we can get started on the mail."

"Lead the way, Detective," he chirped. Beckett stifled a sigh and started walking.

"So," said Castle as they settled into chairs in the briefing room, pulling on protective gloves before they began on the stack of fan mail, "what's the deal with you and Mr. Stuck-Up Federal Agent?"

"I don't know what you mean," Beckett said quellingly, which of course had no effect on him whatsoever.

"Come on," he said with his annoying smirk, "like, you're dating him and working a case with him; that's gotta be awkward, right?"

Beckett felt her mouth fall open. "How did you-" She stopped herself abruptly and firmly closed her mouth again, cursing the burning of her cheeks.

"Oh," Castle said, his eyebrows going up curiously, "is it supposed to be a secret? My bad."

Beckett blew out a frustrated breath. "Why are you here?" she couldn't help asking, her tone betraying her irritation. "You don't care about the victims, the case, any of this." She sharpened her glare, wishing it could do any real damage. "So what is it, Rick? Are you here to annoy me?"

"I'm here for the story," Castle replied simply. "Why these people? Why these murders?"

Beckett sighed, the fire draining out of her, leaving her simply feeling embarrassed at having lost her cool. "Sometimes there is no story," she said with resignation. "Sometimes the guy is just a psychopath."

"No." Castle shook his head firmly. "There's always a story. Always a chain of events that makes everything make sense." He tilted his head, studying her. "Like you, for example, and Federal Agent Man."

"Agent Sorenson," she corrected wearily.

"Whatever. The point is, it doesn't fit. _You_ don't fit. Not here, and not with him." Castle's smirk was gone; his expression was serious now, contemplative, his eyes not leaving her face as he spoke. "Smart, good-looking women like you become doctors or lawyers; they marry doctors or lawyers. They don't become cops dating federal agents. Yet here you are. Why?"

Beckett shifted in her seat, trying not to let her discomfort show, but well aware that she was letting Castle get under her skin in exactly the way she had vowed not to. "You're the novelist. You tell me," she snipped, picking up an envelope from the box of fan mail. She slipped the letter out, pretending to find it much more interesting than Castle.

But he wasn't put off; he leaned back in his chair, studying her openly. She tried to ignore the way goosebumps went racing across her skin under his gaze. His lips were curled in the tiniest of smiles, just enough to bring his face alive with intrigue - so much more attractive than the fake persona he usually wore, she caught herself thinking.

"Well, you grew up in Manhattan, that means money," he said with a judicious nod. "You went to a good college; you had lots of options, but you chose this. That tells me something happened."

Beckett blinked. With an effort, she kept her poker face in place, an unpleasant mixture of emotions swirling through her. Anger, grief, and reluctant admiration - Castle was smarter than he let on, more insightful beneath the carefree façade than she would have guessed.

"Not to you," he went on, "you're not that wounded, but it was someone you loved. And you probably could've lived with it, except that the person responsible was never caught."

She stared at him for a long, tense moment, feeling frozen, unable to speak. How had he guessed all of that, just from a few minutes' interaction with her? And more than that - how did he manage to make her sound noble, rather than simply broken?

"Cute trick," she managed at last, her voice coming out creaky through a dry throat. "But don't think you know me."

Castle cleared his throat and looked away, suddenly seemed unaccountably embarrassed. "Well, I still haven't figured out how it leads to you being with someone like him," he said, shaking his head as if in disbelief. Beckett bristled, but he went on before she could muster up a defense of Will. "But the point is, there's always a story. You just have to find it."

The thought flickered through Beckett's mind that Castle had shown more interest in her history in the past five minutes than Will had shown in all their months of dating and working together. Will knew about her mother's murder, of course, but he had never asked for details - and he sure as hell hadn't shown any curiosity about how that one moment in her past defined who she was as an adult.

But as quickly as it had come, she pushed that thought away, and forced her eyes to focus on the piece of paper in her hand as she unfolded it. And felt a sudden jolt of excitement as she realized what she was looking at.

"I think I just did."


	3. Chapter 3

A little while later, Beckett was back in the bullpen, on the phone with the CSU lab. The letter she had found bore a drawing, a crude rendition in crayon of the crime scene - blood-red roses on the body and all - with the words _THIS IS YOUR GRAVE_ scrawled angrily across the bottom. Castle's eyes had widened when he saw it, and the other detectives and Sorenson had reacted similarly.

Beckett had sent Ryan to hand-deliver the sheet of paper and its accompanying envelope to the lab, and she and Castle and Esposito had quickly skimmed through the rest of the fan mail, finding nothing else from the mystery sender. Now, with Castle looking far too comfortable in the chair next to her desk, she was listening to the lab technician run through the preliminaries.

"Uh-huh," she said, "okay," and watched as Sorenson came out of the restroom, noticed Castle in the chair, and scowled briefly before visibly reminding himself to stay cool.

Castle, meanwhile, had torn his eyes from Beckett long enough to spot Sorenson, and a small smirk twisted the writer's lips as he returned his attention to Beckett. She sighed. Just what she needed: a bunch of masculine posturing bullshit for her to babysit while she was trying to solve a case. And the lab tech was being singularly unhelpful.

Grimacing, she hung up the phone. "Lab's got lifts off the letter," she announced, forestalling whatever Will might have been about to say on the subject of Castle sitting in the chair where he, Will, usually sat when he visited the precinct.

"Whose?" Castle asked eagerly. She shook her head.

"The system's backlogged. It'll take a week to run a match."

"A week?!" Castle exclaimed, in near-unison with Sorenson. Beckett pursed her lips to hold back a grin; Esposito, unnoticed at his desk behind them, snickered openly. She shot him a glare.

"Welcome to reality," Beckett said to Castle with a shrug. He scoffed.

"Never did much like reality," he said, pulling his cellphone from a pocket. Sorenson was doing the same, and they both paused, looking at each other.

"What do you think you're doing?" Sorenson demanded.

"Calling the mayor's office," Castle shrugged with exaggerated casualness. "He's a big fan. Why, what are _you_ doing, Agent?"

"Calling the FBI lab," Sorenson grumbled. "They can download the scan from the NYPD data banks and run it through our own processing software in a fraction of the time."

"Well, doesn't that sound fancy," Castle said with his trademark smirk. Predictably, Sorenson bristled.

"Like pulling strings with the mayor is going to work?" Will demanded. "You're just showing off."

"I can get the results," Castle insisted, frowning slightly, though he remained slouched casually in the chair, apparently unconcerned by the need to look up at Will. "At least I'm playing within the system. Your solution is apparently to keep your cool toys to yourself."

"I do not-"

"Oh, for god's sake!" Beckett burst out, unable to stand the bickering any more. "Why don't you both just drop your pants and get it over with?"

Castle's expression cleared, his frown dropping away, replaced by a mischievous twinkle in his eye. "I'm game," he said easily, looking a challenge up at Will.

Sorenson glared at him, but Beckett cut in again before he could respond.

"The fact is, the FBI system will be faster, so make your call, Will." For once, Will didn't bat an eye at being told what to do. He simply turned away, raising his phone to his ear.

Beckett turned her attention back to Castle. "Half the guys here are waiting for prints from our lab. You don't just jump the line."

"Right, right." He shook his head at her. "And you always come to a complete stop at a red light, and you never fudge your taxes." Castle sat up a little straighter in the chair, leaning toward her, lowering his voice insinuatingly. "Tell me something," he murmured, "do you ever have any fun? You're dating the most boring guy in existence. Don't you ever get the urge to let your hair down?"

"You do know I'm wearing a gun?" she snapped back, exasperated, but once again Castle refused to take her seriously. He just quirked an eyebrow, his lips curling in that infuriating smirk. Beckett hated herself more than a little for how her eyes were drawn to that annoying mouth of his.

Before she could say or do anything else instantly regrettable, Ryan piped up from his desk, where he was just hanging up the phone. "Beckett!" he called. "They found another one, midtown."

"Shotgun!" Castle yelled as Beckett, Ryan, and Esposito jumped up from their chairs, reaching for their jackets. They all stopped in their tracks and turned to stare at the writer - Beckett in irritation, the two junior detectives in amusement.

"Bruh," Esposito said, shaking his head disdainfully.

"What?" Castle asked with a shrug. "You gotta call it to get it, boys."

"Castle, shut up," was all Beckett said, more of a sigh than a bark as she strode for the elevator with the three men in tow.

She pushed the button to summon the elevator, but it wasn't until the double doors slid open that she belatedly remembered her boyfriend. Castle and the detectives were already inside the elevator car, but Beckett paused in the doorway, turning to look back across the bullpen.

"Sorenson!"

Will was just emerging from the interview room where he had retreated to make his phone call. His head came around, spotting the others holding up the elevator, and he jogged over to join them.

"Another body," Beckett explained tersely, and Will nodded without a word, wearing his usual expressionless federal-agent mask as the elevator began to descend.

Beckett stared straight ahead as well, trying not to think about the fact that, for a minute there, she had almost completely forgotten Sorenson even existed.

* * *

When they stepped through the glass door into the humid, chlorine-scented fitness center in the apartment building, Beckett had to restrain a childish impulse to turn to Sorenson and say _I told you so_. Two murder scenes staged to look like Castle's books might be a coincidence - although that in itself was a stretch - but three? There had to be a connection. Beckett was even more sure of it now than she had been when she first saw Alison Tisdale.

" _Death of a Prom Queen_ ," Castle murmured, staring at the corpse floating face-down in the pool. Of course, Beckett realized, this was his first time at a crime scene; seeing the pictures of the other two bodies wasn't at all the same as seeing one in person. She was glad to see Castle reining in his goofy persona, showing the appropriate respect for the victim, his expression pensive as he studied the scene.

"Stay here and don't touch anything," she instructed him, and went to consult with the CSU technicians. Sorenson tagged along, which she didn't comment on, as long as he was behaving himself and keeping quiet for the moment.

"So this really looks like another of his books?" Will asked when they had finished discussing how to secure the crime scene.

Beckett turned to him with a nod. "Yeah," she confirmed, "it's not one of his better-known ones, but the staging is unmistakable." Past Sorenson's shoulder, she caught sight of Castle crouched down next to the victim's body, talking to Lanie as she began her preliminary examination.

"Excuse me," Beckett said to Sorenson, and strode over to scold Castle for not staying where she had left him.

To her annoyance, Lanie seemed impressed, and Castle had noticed a few subtle details about the body that he was only too happy to point out. Beckett was almost ready to snap at him when Sorenson came over, his steps quick, his face alight with excitement.

"We got a match on the prints," he announced breathlessly. "Kyle Cabot, lives in Brooklyn. Got the address."

"Let's go," Beckett exclaimed, and they were off.

* * *

"So, what, that's it?" Castle asked, a few hours later, as they all stood in the observation room watching Kyle Cabot rock back and forth wordlessly on the chair in interrogation.

"What more do you want?" Beckett asked with a lift of her eyebrow. "Evidence is in his apartment, and we can connect him to all three victims. Two from the diner where he worked, and Tisdale was his social worker."

"It's a good collar," Sorenson agreed, nodding. He caught Beckett's eye and gave a little shrug, an embarrassed grimace, which she took for an apology and a tacit acceptance of the _I told you so_ that she hadn't voiced. She nodded back, and saw his shoulders relax almost imperceptibly.

"No," Castle protested. "It's, it's too easy. The reader would never buy it."

Will scoffed and turned away with a shake of his head. Beckett fought back a surge of irritation at both men, and said merely, "This isn't one of your books, Castle. Around here, we find a guy standing over a body with a gun, he's usually the guy who did it."

Castle was still clearly displeased with the outcome of the case - as was Sorenson - but Beckett had no more patience for either of them. She turned on her heel and strode out to the bullpen to arrange a court-appointed lawyer for Kyle Cabot.

When she got off the phone, the two men were nowhere to be seen, but Sorenson reappeared a few minutes later, as she was taking down the murder board. "Give you a ride home?" he offered.

Beckett pursed her lips and considered his offer as she put the victims' photos into the box on her desk, along with the rest of the case paperwork.

There was no good reason to refuse Will's offer, and no good reason to keep the evidence around now that the case was closed, and yet...

"Sure, okay," she said after a moment, forcing a smile for her boyfriend. But she left the box containing the case file on her desk, rather than taking it down to the evidence room.

* * *

Settling into the passenger seat of Will's SUV as he navigated through evening rush-hour traffic, Beckett gazed out the window and felt frustrated.

There ought to be conversation, she couldn't help thinking. She and Will had been together for long enough now that they should be chatting naturally during the drive, and it should feel easy, comfortable. So why did she always feel so awkward around him, straining to find a topic to bring up?

She felt that the burden was on her to start the conversation, whatever it might be, because after all, she had been right about the Castle connection to the Tisdale case, and Will had accepted it with good grace. So she wanted to be conciliatory, to be girlfriend-y. She just wasn't sure she even knew how to do that. Things were so strained between them lately, and she knew it was mostly her fault.

"So," she said after a few minutes' thought, "what's going to happen with the Solesino case now? Can they still prosecute it without Tisdale's testimony?"

"The D.A. seems to think so," Will answered. "There are other witnesses, and we have Tisdale's preliminary statement."

"Good," Beckett murmured. "That's good."

She sighed and grimaced, mentally kicking herself. That had been a dumb topic to choose. The case was probably confidential, and there wasn't much that Will was allowed to say about it.

He seemed fidgety, tapping his fingers on the steering wheel as they sat waiting for a traffic light to change. Beckett studied his profile, wondering again what she was missing. What was a person supposed to feel when she looked at her boyfriend's face? When she looked at Will, she didn't feel much of anything in particular. What was wrong with her?

Maybe Lanie was right. Maybe the only reason Kate was with Will was exactly that - because he didn't make her feel anything in particular. Maybe that made it easy for her to keep him at arm's length, to protect herself from getting hurt.

Was that what she was doing?

She pushed that thought aside firmly, her frown deepening.

"Any news on that promotion you were hoping to get?" she tried, wondering if that might be why Will was so preoccupied. He glanced sideways at her, then returned his attention to the road, shaking his head slightly as the car began moving again.

"No," he said with a sigh. "They did say the process could take a while. Here we are," he added as he pulled the car up to the curb. "Okay if I come up? We could, uh, get some takeout?"

"Yeah," she agreed quickly. "Sure."

The process of choosing a restaurant, studying the menu, and ordering the food occupied them for a while, and soon enough they were settled in at Kate's dining table with their plates.

"How's your dad?" Will asked politely as he dished out noodles from his takeout container.

"Fine," Kate answered. "He's actually on a business trip on the West Coast right now, so I haven't talked to him in a couple days. But he's good. We're planning a trip up to his cabin when he gets back."

"Won't that be cold this time of year?"

"Yeah, but it's going to start to warm up soon," she said, adding with a touch of humor, "supposedly."

They talked about the weather for a while, and then about Will's parents, and his younger sister who was just starting grad school. Kate felt relieved that the conversation managed to keep flowing, although it still felt stilted to her, forced. But at least they were talking.

When they had finished eating, she put on the coffee pot and excused herself briefly. Upon returning from the bathroom, she found Will standing in front of her bookshelves, hands in his pockets, his lips pursed as he looked over the empty space where her Castle books usually stood.

"Cream and sugar?" she asked, moving past him to pour the coffee.

"Yeah, thanks," Will said. He gave the shelf one last look and then turned away from it, back toward her. "If he only knew how big a fan you really are."

"What?" She glanced at the shelf, her forehead creasing. "Castle? Yeah, well, he's not going to know. The case is closed."

Will accepted the cup that she gave him, but instead of sipping, he just held it in his hand and stared at Kate, a strange light in his eyes that she didn't understand. "Maybe he should."

"Should what?" She sipped her own coffee in self-defense, confused. "You're not making any sense, Will."

"I think you should do it," he burst out, his square jaw set with determination. "You should sleep with him."

Kate nearly dropped her coffee cup on the countertop, her mouth falling open in shock. "Wh - What?!" she exclaimed, astonished. But Will simply nodded.

"Yeah," he said. "You should. He's on the freebie list, so it's okay. It's allowed. You can get it out of your system."

"Will..." She gulped her coffee, barely even tasting the hot liquid as shock seemed to have numbed her whole body. "You can't be serious. That's not - The freebie five list isn't meant to be taken that seriously! It's just a stupid game for couples to get to know each other better."

He frowned. "Well, I get it, most people will never meet the celebrities on their lists so it's moot. But come on, you met yours for real, and I know you're attracted to him."

Beckett bit her lip, wishing she could deny it. Damn it, Castle was so annoying, so frustrating... and yet... yeah, she was attracted to him. Very much so. Even more so, in fact, now that she'd had a chance to see how his clever mind worked, to get a few glimpses of the intellect behind his carefree façade. But that was _not_ the point.

"Will, that's crazy," she said, surprised to hear a tremor in her voice. "I'm not going to cheat on you."

"I don't think it counts as cheating if I gave permission," he shrugged. He sipped his coffee, appearing unconcerned. Kate could only stare at him, trying to figure him out. Could he possibly be as blasé about this as he seemed? Had he given this a lot of thought?

Without really meaning to, she found herself thinking about Castle. He was tall and broad, like Will - taller, in fact. Unbidden, without her conscious volition, her mind supplied an image of Castle's body on top of hers, pressing her into the mattress. His naked skin would be warm, and his mouth-

"No!" she said aloud, shoving the mental image away. She folded her arms over her chest and frowned at Will. "No," she repeated. "You're out of your mind. Even if you did give... 'permission'... it would still be cheating. It would still _feel_ like cheating."

"It's a free pass, Kate," he said with lifted eyebrows. He put his coffee cup down and came around the kitchen counter to her, putting one hand lightly on her elbow. "You want to do it, so you should do it."

At a loss for words, she examined his face, searching for a sign that he was joking, although she didn't really expect to find it. She knew Will better than that; he wasn't much of a joker, and this was definitely not the kind of thing he would find funny.

"No," she said yet again. "I'm not going to sleep with Castle. Can we just... not talk about him any more?"

Will gazed at her face for a long moment, and then nodded, a small smile lightening his face. "Okay," he agreed. "Sure." He bent down toward her, and she unfolded her arms and allowed him to kiss her. She rested her hands on his chest and let him pull her closer, kissing her more deeply.

But when he moved his hands to the hem of her t-shirt and began sliding it up her back, Kate pulled away, wincing.

"I'm - I'm not, uh, it was a long day," she stammered. She averted her eyes, unable to look Will in the face. "Sorry," she added uncomfortably.

Will let go of her, taking a step backward. "Uh, okay," he said, sounding confused. "I'm sorry."

"No..." Kate forced herself to look at him, to give an apologetic smile. "It's fine. I'm just... tired."

"I should go then, I guess," Will said, not moving, staring at her with a frown. She frowned back, unsure what he wanted from her, what he was waiting for.

"Uh, dinner tomorrow?" she offered as an olive branch. "I'll just be doing paperwork unless we catch a new case, so it should be an early night."

"Yeah. Okay." He moved at last, turning away with a shake of his head that Kate didn't understand.

She saw him to the door, where they exchanged awkward cheek-kisses and goodnights, and then he left. As soon as the door closed behind him, Kate breathed out a sigh of relief.

Just as quickly, she felt guilty and ashamed of her behavior. Maybe she should have just gone along with it, taken Will to her bed, to avoid the discomfort and hurt that she was pretty sure she'd seen lurking behind his eyes.

But... on the other hand, maybe not. Why should sex with her boyfriend be an unpleasant chore? That wasn't normal for a healthy relationship, was it?

Sighing again, she put the coffee cups in the sink and went to the bathroom. She hadn't been entirely truthful when she'd told Will that she was tired - it hadn't really been any longer of a day than usual - but she might as well make good on it.

As she undressed, she found herself remembering the bath she'd taken the previous night, and the way Castle had intruded on her thoughts as she lay there in the hot water. Squirming internally, she opted for a shower instead.

It didn't work. Castle popped up again, unbidden and unwanted, as she was standing in the tub with the water streaming down her body. In her mind's eye she saw him looking her up and down, much as he had done when they first met the other day. But this time she was naked, and Castle's bright blue eyes burned hot with passion as he stepped forward and -

"Shit!" she exclaimed aloud, and then groaned in mingled irritation and embarrassment. She twisted the knob, turning the water almost ice-cold, and finished her shower in a rush, scowling.

She put on pajamas and defiantly took a James Patterson novel off her shelf. But as she was preparing to get into bed and read, the phone rang. She sighed when she saw her friend's name on the caller ID.

"Hello?"

"Hey, Kate."

"Hey, Lanie." Beckett plopped down onto the edge of the bed, already rolling her eyes. "What's up?" As if she didn't know.

"Don't play innocent, girl. Come on! Rick Castle?"

"Lanie, don't start with me," Beckett pleaded, wincing at how whiny her voice sounded.

"Oh, I'm starting," her friend chuckled. "That man is like a gift from above... and you should unwrap it. And by unwrap it I mean-"

"I know what you mean," Kate interrupted hastily. "But need I remind you, I'm in a relationship."

"Seriously, Kate. You should ditch Will and hop on that Castle train. I bet that man gives a hell of a ride."

Beckett scrunched up her face, trying not to blush. She reminded herself that her friend had no way of knowing what thoughts had been going through her mind about Castle - let alone Will's ridiculous suggestion. "Lanie, no. Come on. I'm not dumping Will for a one-night stand."

"Who's to say that's what it would be? He's smart, funny, you love his books..."

"Please." Beckett scoffed, ignoring the frisson that rippled across her skin at the thought. "The guy's like this big celebrity. He can have any woman he wants."

"Girlfriend, when are you going to wake up and look in the mirror? You could be that woman, if you'd just get the stick out of your butt and give him a chance."

Kate didn't know what to say to that. Yes, Castle had flirted a bit, but he was probably like that with everyone. Wasn't he? Sure, Beckett knew that she was hot, but Castle probably had dozens of equally hot women in his little black book, and none of them had complicated pasts and emotional walls like fortresses around their hearts.

"It doesn't matter," she said quietly, as much to herself as to Lanie. "I'm with Will, so it's moot."

Lanie sighed. "Okay," she said. "If you say so. Lunch sometime soon?"

"Yeah."

After saying her goodbyes and hanging up, Beckett got into her bed and opened the book. She focused resolutely on the story, refusing to let her mind wander away from the words on the page. She sat up reading until her eyelids drooped, then turned off the light and fell into a deep, dreamless sleep.


	4. Chapter 4

Stepping off the elevator onto the homicide floor the next morning, Beckett was in a decent mood for once. The case was closed; she could put the infuriating and discomfiting Castle out of her mind; she should be able to finish up the paperwork by lunchtime, and then, after work, if there was no new murder, she would go to dinner with Will and make sure things were okay between them. Everything in her life was nice and tidy again.

Until she came around the corner and discovered Castle sitting in her chair, rifling through the file folders on her desk.

"What are you doing?" she demanded, ignoring the twist of shock and anticipation that seized her guts. She darted forward and snatched the papers out of his hands, glaring.

"Just a habit," he shrugged, unconcerned. "Poking through people's mail, their medicine cabinets."

"Why are you still here?" Beckett asked, hiding her discombobulation behind the bite of her sharp tone.

"I just came by to give you this," he said, standing up and taking a gift-wrapped package from the messenger bag over his shoulder. "Just a little something to memorialize our brief partnership."

Beckett paused, her eyebrows drawn down into a frown, looking at Castle. The word _partnership_ had jumped out at her, made her heart give a little stutter in her chest.

In the professional sense, she had always been happiest without a partner. She had Ryan and Esposito, but they were subordinates; she was the alpha member of their team. It worked best. Even when she'd taken on that kidnapping case with Sorenson last year, the one that introduced them to each other, it had only worked out because it was a temporary arrangement. They weren't partners, exactly; they were the heads of two separate teams working together. That was how Beckett liked it. She didn't need or want a partner. She worked better on her own.

So why did it give her such a strange sensation in the pit of her stomach when Castle said the word?

"Don't look so suspicious," he urged, nudging the package into her hands. "Go on, open it."

She looked down at the neatly wrapped gift, still frowning slightly, and lifted the cover off the box. Nestled inside was a copy of Castle's new book, _Storm Fall_.

"I got you an advance copy," he said, watching as she opened the front cover to find his autograph scrawled across the title page. "Not that you're a fan."

Beckett pressed her lips together, fighting to keep her expression neutral, even as her heart was giving a little flutter of pleasure. "Thanks," she said quietly. "That's actually kind of sweet."

She lifted her eyes to Castle's face again and found him gazing at her with a small smile, softer and somehow more... genuine than his usual persona. Her guts twisted again, hard.

"It was nice to have met you, Detective Beckett," he said. He held out his hand, and she took it automatically.

"Um... likewise," she managed, feeling awkward. His hand was large and warm, and the simple touch sent hot shivers rushing across her skin. The subtle, spicy scent of his aftershave teased at her nose, making her knees suddenly feel liquid.

He lingered over the handshake, clasping her hand just the slightest bit longer than strictly appropriate. Then he gave her a nod, released her hand, and walked away.

When she turned to watch Castle go, Beckett found Will standing at the other end of the bullpen, watching them. As Castle disappeared down the stairs, Sorenson came forward, approaching Beckett, who ducked her head, wincing.

"It's not what you think," she said weakly. She sank into her chair, staring at the book in her hands. Her head felt cloudy with confusion, with the smell of Castle, the lingering heat of his touch, the phantom imprint of his hand on hers.

"If you say so. What was he even doing here then?" Will asked skeptically.

Beckett opened her mouth, then paused, her eye falling on the pile of file folders stacked at the corner of her desk.

Oh shit. "He didn't," she gasped. The fog cleared from her brain in a blink, her spine straightening as she reached over to flip open the folders, confirming what she suddenly knew - they were empty. "He did." Her skin flushed hot again with humiliation... and anger. "He took the file!"

"What?" Sorenson exclaimed.

Beckett shot up out of her chair again, her thoughts whirling. He couldn't have gotten far. She dashed for the stairs with Sorenson close behind. As the rapping of her shoes on the concrete filled the stairwell, she vaguely heard Will barking into his phone, but she was laser-focused on her target, hurtling down the stairs and out the front door.

By the time she and Will attained the sidewalk, another FBI agent had stopped Castle in the act of getting into a taxi. Horns were honking, the cab angled halfway into the flow of traffic as the agent stood with the rear door open, arguing with the occupants.

"Richard Castle, get out of the taxi," Beckett snapped. "You're under arrest for felony theft and obstruction of justice."

"You forgot making you look bad," the writer replied cheerfully as he climbed out, holding his messenger bag. The other agent loomed behind Beckett, alert in case Castle might try to make a break for it; Sorenson was flagging down a couple of passing uniforms for backup. The taxi peeled away into traffic with a disgruntled screech of its tires.

"You know," Beckett said, reaching into her pocket for her handcuffs, "for a minute there, you actually made me believe that you were human."

"Ooh, bondage," Castle grinned. He held out his hands to allow her to cuff him. "My safeword is apples." He leaned closer to murmur in Beckett's ear. "What's his? Vanilla?"

Beckett flushed again, her scowl deepening. "Take him to lockup," she instructed the two uniforms.

"By the way, the rose petals in the Tisdale murder?" Castle said as the uniforms took hold of his arms. "They're grandiflora, not hybrid teas."

"I'll make a note of it," Beckett said, rolling her eyes, glancing at Sorenson, who was standing aside to let her make the collar.

"Yeah, you should, since it means Kyle Cabot is innocent," Castle called over his shoulder. The officers shoved him up the stairs of the precinct house and through the door.

"What's he blathering about now?" Sorenson asked, coming closer to Beckett. She shook her head slowly, her thoughts beginning to spin.

"I'm not sure," she lied, chewing on her bottom lip. The rose petals... and the dress on Kendra, the pool victim, had been the wrong color... But did it mean anything?

* * *

"He did what?!" Captain Montgomery exclaimed when Beckett briefed him on the Castle situation. Sorenson stood in the doorway of the captain's office, lurking in the background as he liked to do.

"He seems unhappy with the resolution to the case," Beckett said, pinching the bridge of her nose with her fingers. Castle was giving her a headache... again. "I've got him in lockup downstairs, but if you want me to release him, sir, I-"

"No," her boss said, shaking his head slowly. "Let him stew for a while, just to let the point sink in. He can bail himself out at end of shift."

"Yes, sir."

"Dismissed."

Back out in the bullpen, Beckett turned to Sorenson with raised eyebrows. "What brings you here anyway, Will? I thought we were doing dinner."

"Oh, yeah, we are," he agreed quickly. "I actually just came to get a copy of Alison Tisdale's autopsy report. Thought I'd come up and say hi since I was here."

"Oh. Okay," she said, and produced a smile that she hoped was convincing. "Well, uh, thanks for the help with everything."

"Any time." He smiled back. "I'll see you tonight? Meet you back here at end of shift?"

"Yep, sounds good."

After Will had gone, Beckett was finally able to throw herself into the paperwork. It wasn't exciting, but it served to distract her mind from the Castle situation for a little while.

Too soon, though, it was noon and her junior detectives were wandering over, giving her curious looks.

"What?" she demanded, clicking Save on her latest report and turning her attention to them.

"Heard you arrested Castle this morning," Ryan commented.

"Yeah," Esposito agreed with a nod. "What's going on with that, anyway?"

"Don't know what you mean," Beckett replied shortly. "Castle tried to steal the case file, I stopped him. That's all that's going on."

Esposito and Ryan exchanged a look, but if there was anything more they wanted to say on the subject, neither had the nerve to do it.

"Remy's?" Ryan asked instead, and Beckett glanced at the clock and nodded.

"Yeah, just give me a minute."

* * *

The rest of the day went by in relative quiet. Beckett finished writing up the case files for the three murders and filed them, emailing a copy to the D.A. and another to Sorenson as a courtesy. Late in the afternoon, Montgomery authorized Castle to be released, calling his mother to come and pick him up.

The flighty Martha Rodgers brought Castle's daughter with her, the redheaded teen whom Beckett had seen briefly at the book party. "I hope my dad wasn't too much trouble," the girl said politely to Beckett. "He probably loved being locked up. It'll go into his next book for sure."

"If he ever manages to write it," her grandmother muttered. Beckett's eyebrows went up in surprise. What did that mean?

"Gram," Alexis chided. "You promised."

"Oh, I know, yes, darling," the older woman agreed with a wave of her hand. "But after all, the new book is out, and instead of working on the next one, what is he doing? Running around playing cop, getting himself arrested." She turned her attention to Captain Montgomery. "Is he in a terrible lot of trouble, Captain?"

"Well, we do take obstruction of justice very seriously," Montgomery replied, "but considering the extenuating circumstances, we've decided not to file any charges. He's got to promise to behave himself from now on, though."

"Oh, he will," Martha assured him. "We'll see to that." The teen by her side nodded emphatically.

Just then the man in question stepped off the elevator, accompanied by a uniformed officer. At a nod from Montgomery, the officer unlocked the handcuffs and allowed Castle to step forward to greet his family.

"Hello, father," his daughter said, looking him up and down with an assessing gaze.

"Hello, daughter," he replied, pulling her in for a hug. "Mother," he added, over the girl's head. "I see you've met Detective Beckett and Captain Montgomery."

"Yes, yes," Martha confirmed, "and they've agreed to drop the charges if you agree to behave."

"No more interference with the case, Mr. Castle," Montgomery said firmly. "Do we understand each other?"

"Yeah," Castle said, his eyes locking with Beckett's. "But you still got the wrong guy."

Beckett's eyebrows drew downward into a frown as she watched him put his arms around both redheads' shoulders and lead them away. Chewing on her lower lip, she went back to her desk and looked at the small pile of photos and papers from the case files that Castle had taken. After being processed through as evidence a second time, they had been returned to her again for re-filing.

Still frowning, her thoughts turning over and over the facts of the case, she found herself taking the pictures out of the folder and posting them onto the murder board again. The words she had written on the whiteboard were still there, and she carefully fit each photo back into its spot, using magnets to clip them in place.

She was perched on the edge of her desk, lips pursed, studying the board, when her boyfriend arrived.

"Oh, no," Sorenson groaned when he saw the resurrected murder board. "Don't tell me he got to you."

"Please, he didn't get to me," Beckett denied, not taking her eyes off the interconnecting lines and scrawls of information. "She did." A wave of her hand indicated the photo of Alison Tisdale, prominently displayed in the center of the board.

"Alison?"

"She doesn't fit," Beckett mused, running a hand over her chin as she went over the details yet again. "He starts with a murder of convenience, someone he knows from the diner where he works. Escalates to a murder of someone he knows very well, the social worker who got him the job. The only one who had ever cared enough to actually help him, according to Cabot's file."

"So?" Sorenson asked, shifting on his feet, doing a poor job of concealing his impatience.

"So, then he goes back to a murder of convenience, someone else from the diner. It doesn't make sense."

"You caught the guy, Kate," Will said, putting a hand on her arm. She winced, more at his gently condescending tone of voice than the words or his touch. "All the evidence is there," he went on, "it all points to him. It was him."

"But there are too many details that are wrong," she insisted. "The murder weapon on Fisk, the roses on Tisdale, the dress on Kendra. For an obsessive, it would be impossible not to get those details right."

"So you think Castle was right." Will's face twisted with displeasure.

Beckett grimaced also. Reluctantly, she turned away from the murder board and picked up her coat from the back of her chair. "Yeah," she admitted as she put her arms into the sleeves. "I hate to admit it, but I do think he was right." She opened her desk drawer and took out her purse.

If left to her own devices, she might sit here all night staring at the murder board and going over and over the facts of the cases until her eyes crossed, so it was just as well that Will had shown up to take her to dinner. Even if she was getting more than a little annoyed at him and the patronizing way he was talking about the case, dismissing her concerns.

"So are you reconsidering?" he asked, as she began to button up her coat. "About the... you know. With Castle."

She shot him a glare. Was he still on that? "Really?" she asked, using her quiet-but-deadly tone. "You're going to bring that up again? I told you, I don't cheat."

"Okay, okay." Will put his hands up in a gesture of surrender. "Never mind that. Let's get to dinner - I want to tell you all about Boston."

Beckett paused, blinking in surprise at the apparent non sequitur. "Boston? What about it?"

"The job. The promotion I was telling you about," he said, his face animated at last, alight with excitement. "I got the official offer. The job is mine, and they want me to start ASAP."

She frowned and folded her arms defensively across her chest, feeling an icy chill run down her spine. "Will, you never said anything about the job being in Boston."

"Oh. Well, I didn't want to get into details before it was a sure thing," he said, waving a hand as if to shoo that away. "But, Kate, you're going to love Boston. The temporary apartment they got me is right on the water, amazing views. And the FBI training facility is state of the art."

"Wait a minute," Beckett said, the ice of her surprise melting quickly into the heat of anger. "Are you just assuming that I'll move to Boston with you?"

"I..." Sorenson stared at her, taken aback. "Well, I mean, we're together. And it's a great opportunity. The FBI has openings that you'd be perfect for, but if you wanted to apply to the Boston PD, you could do that too. Whatever you want."

"Whatever I want?" she repeated, incredulous. "Will, you're making plans to completely uproot my entire life without even asking me. Didn't it even occur to you that maybe I don't want to leave New York?"

He didn't answer immediately, his mouth opening and closing several times, clearly at a loss. His silence only served to make her angrier, and she bit back the urge to yell at him. The last thing she needed was for the night shift at the Twelfth to be witness to an ugly fight between Beckett and her boyfriend.

"I thought you'd be happy," Will said at last, his face crumpling into a sour mixture of disappointment and bewilderment. "It's a great opportunity for me, for both of us. A change of scenery. And we could still be together."

Beckett took a deep, careful breath, and then another. When she felt that she could control her voice, she spoke quietly, low and harsh with the strain of holding her emotions in check.

"You should have told me this from the beginning," she grated out. Before he could reply, she added, "And if you honestly thought that I would consider leaving everything I have here just to be with you... then you don't know me at all."

She pulled the strap of her purse over her shoulder and stalked away, heading for the stairs. A part of her was cringing, expecting Will to come running after her, calling her name; but he didn't. She wasn't sure whether to be grateful or even more angry.

As soon as she exited the building and attained the sidewalk, she turned and began to walk, her strides long and fast. Her apartment was fairly far, but she was too filled with furious energy to sit still in a car in traffic or on the subway. She needed to burn off some of her anger in motion.

Other pedestrians scooted out of her way as she barreled along the streets of Manhattan, seething.

How could Will have misjudged her so badly? No - how could _she_ have misjudged _him_ so badly? She had known that he was a bit of the old-fashioned type - always insisted that he should pay for their dates, held the door for her, and so forth - but she'd seen that as part of his charm, tried not to be weird about it. He'd always treated her with respect, in the personal as well as the professional arena.

( _Until this case_ , her inner voice whispered nastily. Her scowl deepened.)

But this... this was a bridge too far. For him to honestly believe that she would be happy, excited to move hundreds of miles away from home - without a definite job lined up - far from her dad, her friends - leaving her mom's murder behind, still unsolved - it was incredible. Maybe even unforgivable.

She stopped at a corner to wait for the light to change, and blinked, taking in her surroundings. She had walked farther than she'd realized while consumed with her thoughts. She was more than halfway home, and as she stood there with a small crowd of fellow pedestrians while the traffic flowed past, her eye fell on a small marquee on the other side of the street.

It was a small independent movie theater, and the sign indicated that it was currently showing a John Woo marathon. Yes, she thought, that was exactly what she needed: to escape into a loud, violent, fast-paced action movie, to distract her and stop her mind from spinning around in angry circles.

The Walk sign came on; she crossed the street and bought a ticket for the next show.

Two movies later, she came back out of the theater, feeling much calmer, almost numb. She wasn't sure what was going to happen with Will, with their relationship, but she wasn't thinking about that now. She would think about it later.

* * *

 _Thank you all for reading and reviewing!_


	5. Chapter 5

Just before noon the next day, Beckett was at Jonathan Tisdale's office building. She had chosen not to bring Ryan and Esposito with her, partly because she didn't want to put Tisdale on the defensive - and also because she had a sneaking suspicion that she wasn't going to be interviewing him alone in any case.

And she was right. As she entered the building, she could immediately hear the voice that was already becoming too familiar for comfort. "Hi, I'm Rick Castle," she heard. "I have an appointment to see Mr. Tisdale."

Beckett took a decent amount of satisfaction in seeing Castle thoroughly flustered when she made her presence known. Oh, he was busted, and he knew it. But he recovered surprisingly quickly, following her into the elevator and flashing a grin as he pulled off his sunglasses.

"Good morning, by the way, Detective," he said cheerfully. "Lovely to see you again."

"Don't push your luck, Castle," she shot back. "I could still decide to report you to Captain Montgomery."

"Yeah, but you won't," he smirked. "At least, not until we find out whether my theory is right."

The elevator announced its arrival at their floor with a soft beep, cutting off whatever Beckett might have said in response to that. She ground her teeth together and straightened her shoulders as she strode out into the corridor, determined not to let Castle get to her. Again.

Beckett hated to admit it, but interviewing Jonathan Tisdale with Castle was surprisingly interesting and enlightening. Afterward, out on the street, she took a firm tone again - and a firm grip on Castle's nose when he wasn't complying - to cover up the fact that she was actually impressed. Maybe being a mystery writer had taught Castle a thing or two about detective work. She would _never_ admit that to him, of course.

While Castle was buying a hot dog from the vendor, Beckett chewed on her lower lip and thought over the theory he had expounded. It was true that Alison Tisdale's father didn't look well. If he was really going to die soon, and half of his estate hung in the balance... there might just be something to it.

She kept her mind firmly on the facts of the case, resolutely ignoring how her hand tingled where Castle had grabbed it to pull her fingers off his nose. It was entirely unreasonable the way her whole body had responded to the brief touch of his hands, so she wasn't thinking about it. Really.

"So," said Castle after he had inhaled half of his hot dog, "we're going to interview the brother, right?"

"I'll have to call the precinct, get his address," Beckett answered. She watched Castle applying more ketchup, and she broke. "Okay, fine," she said to the hot-dog vendor, "give me one too. With everything."

"Yeah! That's the stuff," Castle exclaimed, giving an approving nod. "I knew you had it in you, Detective." Abruptly his eyes went wide and he clamped his mouth shut, then changed his mind and quickly stuffed the rest of his hot dog into his mouth.

Beckett glared. She was pretty sure she could guess what kinds of salacious remarks had gone running through Castle's head just then - something to do with sausages and " _had it in you_."

"Castle," she growled.

He spluttered, still chewing the large mouthful of food, and raised his eyebrows in what he probably hoped was an innocent expression. He mumbled something that might have been "What?" in what might have been an injured tone if his mouth hadn't been full.

At last, it was Beckett's turn to smirk. "Bit off more than you could chew?" she needled. She took her hot dog from the vendor, handed him the money, and turned to walk away.

A few steps down the sidewalk, she paused and turned back. Castle was still standing there, looking astonished.

"You comin' or what?" she asked.

* * *

"So," said Castle, sitting in the passenger seat as Beckett wove her car through lunchtime traffic, "Harrison Tisdale is our new suspect. Do we need to call your boyfriend, let him in on the new lead?"

Beckett schooled her expression into her impassive cop mask. "That won't be necessary," she bit out. "The FBI considers the case closed."

She'd been doing so well with avoidance this morning - had hardly even thought about Will at all - but of course now it all started to come crashing back down on her. The fight they'd had last night... Will's new job in Boston... where did it leave them? She grimaced and chewed on her lower lip.

"Ooh," Castle murmured, his eyes glued to her face. "Trouble in paradise, Detective?"

She shot him an angry sideways glance, then returned her eyes to the road as she brought the car to a stop at a red light. "Castle, shut up."

As usual, he didn't listen. "Did you and Mister Federal Agent Man have an argument? Was it about the case?"

Beckett gripped the steering wheel harder than necessary, gritting her teeth.

"Do you want to talk about it?" Castle added.

Beckett turned to stare at him, incredulous. "With _you_?"

"I'm a very good listener," he shrugged. "Besides, I've been divorced twice now, so I know a thing or two about arguments between romantic partners. I'm a veteran, you could say."

"Considering they both divorced you, that's not exactly working in your favor, Castle." She rolled her eyes and shook her head. "Whatever. I'm not discussing this. It's none of your business."

"Suit yourself," Castle said. "But all that tension in your shoulders can't be comfortable."

Beckett took a deep breath and forced herself not to respond. The light changed, and she turned the corner and pulled the car up at the sidewalk.

She killed the engine and then sat for a moment, sighing, as Castle's words from a few minutes ago sank in. Damn it, he was right, though - she probably did owe Sorenson the courtesy of a heads-up.

"What are we-" Castle began, but she held up a hand to forestall him as she pulled out her phone and dialed.

The line connected immediately, but there was a lengthy pause before Will spoke. "Hello?" he said at last, cautiously.

Beckett steeled herself to remain professional. No way was she going to talk about anything... personal... with Will now, while Castle was right here next to her in the car. "Good afternoon, Agent Sorenson," she said crisply. "I was just wondering if your people had spoken with Alison Tisdale's brother as part of the investigation."

She heard Will blow out his breath, almost as if he had been holding it. "Brother?" he repeated. "I don't, uh, hang on a minute." She could hear the clicking of his computer mouse and keyboard. "No," he said eventually, "I don't see anything in here about the brother. Why?"

"Some new information has come to light," Beckett said, choosing her words carefully, already rolling her eyes at Castle's glee, which she could sense from beside her without even looking. "We're heading in to talk with the brother now. Does the FBI want to sit in?"

"Oh, uh..." Will hesitated again. "Uh, as you know, Detective Beckett, we consider the case closed," he said formally. "The Solesino case is going to trial without Alison Tisdale's testimony, and we've agreed with the NYPD's assessment that her murder wasn't related to it. So the FBI has no further plans to be involved."

"Right." She nodded slowly, suddenly feeling awkward. "Well, um, thank you. I'll, uh, I'll keep you informed."

"Kate-"

"Bye," she said hastily, and cut the connection. She tucked her phone back into her purse, already cringing at whatever Castle might be about to say. She almost couldn't bring herself to look at him.

But after a moment she did lift her eyes to Castle's face, bracing herself to order him out of the car... but found only sympathy in his gaze.

"Sorry," he said quietly. Beckett frowned, her hackles going up. She felt irrationally angry at Castle for displaying this softer, less brash side. Why couldn't he just go on being the obnoxious playboy she could comfortably hate?

"Don't be," she grumped, reaching to unbuckle her seatbelt. Castle did the same with his own, but his eyes were still on her.

"I'm just saying, I know how hard a breakup can be," he said. He leaned a little closer to her, his eyes twinkling, a hint of smirk playing around the corners of his lips. "If you don't want to talk about it," he went on, his voice low and husky, "I know some other ways to take your mind off of everything."

Beckett rolled her eyes. Right, there was the annoying playboy again. "You wish," she tossed off. But her gaze was drawn to his mouth, and she was a little startled by how close he was suddenly, leaning across the center console of the car to bring his face near hers.

To her great annoyance, she found that her pulse was speeding up, her skin flushing hot, her mouth suddenly dry as she tore her eyes away from Castle's mouth and forced herself to breathe slowly, evenly.

God, it almost looked like he was going to kiss her, and she wanted him to. She _really_ wanted to kiss him.

Damn it.

"Anyway, we didn't break up," she said, feeling relieved at how steadily her voice came out despite the inner turmoil.

Castle blinked and quickly pulled back, straightening up again in his seat, looking startled. "Oh. Really?" he asked. "That didn't sound like a not-broken-up conversation just now, Detective."

"Well, it was," she insisted. And before he could say anything else, she shoved the door open and got out of the car.

* * *

Beckett's mind was whirling as she and Castle stepped off the elevator on the homicide floor at the Twelfth. Their interview with Harrison Tisdale had been illuminating. He was the killer - she was sure of it; she knew it in her gut - but they didn't have enough evidence yet. Her inner sense of justice was deeply offended, and she knew she wasn't going to be able to rest until they found the key clue that would prove it.

"Detective Beckett," said Captain Montgomery, emerging from the break room with a cup of coffee in hand. He raised his eyebrows, spearing Castle with a look. "And Mr. Castle. Is there something you'd like to tell me, Detective?"

"Yes, sir," Beckett answered firmly. "I'm reopening the Tisdale case."

"Mm." Montgomery regarded her with narrowed eyes. "I suspected as much when I saw that you had put the murder board back up. You have new evidence?"

"Potentially, sir." But she held her tongue, hoping her boss wouldn't ask for specifics. The case was frustratingly thin at the moment, held together by little more than speculation, and she wanted to have more before she laid it all out for her captain.

"Hmm," Montgomery hummed again. "All right, Detective. Keep me posted. And you," he added, sharpening his glare on Castle, "I seem to recall making you promise to stay out of it."

"Which I absolutely intended to do, sir," the writer replied solemnly, "until Detective Beckett here pulled me back in."

Beckett's mouth fell open in astonishment. "I - I certainly did not!" she spluttered. Castle smirked, clearly enjoying her discomfiture, but Montgomery's expression remained steely. Beckett could practically see the wheels turning behind his eyes, but she couldn't figure out what exactly he was thinking.

"Well, you'd better behave yourself," was all he said as he moved past them and returned to his office.

Beckett rounded on Castle with a hard frown, her hand darting out to grab his ear and twist.

"Ow!" he whined, clutching at her wrist and trying ineffectually to pull her away. "Apples, apples. Okay, okay, I'm sorry I ratted you out to your boss." She released his ear and he straightened up, rubbing at it with a slight pout. "I still don't see why we couldn't have just arrested Harrison right then and there."

Beckett rolled her eyes and refused to respond to that. She had already explained repeatedly that they couldn't make an arrest until the evidence was rock-solid. She turned away from Castle, toward the murder board, where Ryan and Esposito stood side by side, arms folded, eyeing Beckett and Castle as they approached.

"What's the deal, boss?" Esposito asked. "We back on the case?"

"We're back on the case," Beckett confirmed. "Harrison Tisdale, Alison's brother. He stands to inherit half of their father's estate, instead of a fourth, now that Alison is dead."

"Her brother?" Ryan repeated, shaking his head. "Man."

"Harrison claims to have been out of the country at the time of each murder," Beckett went on, "even has passport stamps to prove it. For starters, we need to verify his flights."

"I'm on it," Ryan said, sitting down at his computer.

"Tell them how I figured it out," Castle urged. "Come on, Beckett, you didn't tell them it was me."

Esposito looked at her, eyebrows going up. "This joker give you the lead?"

"Please," Beckett scoffed. "I figured it out myself. Castle just got to the father's office a little faster, is all. Probably bribed a cab driver to run some red lights."

"I did not!" Castle exclaimed, affronted. "I was the one who figured out that the father is sick and that the brother was lying. Why can't you just admit that I was right?"

"Because he totally fooled you," Beckett answered. She bit the inside of her cheek to keep a straight face. Castle had been having far too much fun tweaking her; it was time for him to learn that two could play that game. "He totally bought the alibi," she added, to Esposito, who was openly smirking and nodding.

"'Course he did."

"I had a fleeting moment of self-doubt," Castle grumbled.

Beckett was prepared to tease him some more, but then Ryan turned away from his computer and phone with new information, and the four of them were back to work, talking through the facts of the case. Beckett felt the thrill of it overtaking her, a familiar feeling as all of the little clues came together and she knew - she just knew - that they had cracked it.

She could see a spark of the same excitement in Castle's eyes as she went to the phone to call Judge Markway's office.

"Ooh, Markway, tell him I said hello," Castle chirped. Beckett rolled her eyes, but didn't let him derail her. She was on the war path now.

The judge's assistant told her where to find him, and Beckett quickly booted up her computer to put together the search warrant she would need Markway to sign.

"Type faster," Castle urged, making himself comfortable once again in the chair beside Beckett's desk. "If Harrison is smart, he's already destroying the evidence right now."

"Shut up and let me concentrate," she muttered, trying to focus on her screen.

"Do you want me to do it? I can do 85 WPM."

"Castle, _shut up_."

"Kate?"

Beckett and Castle both looked up, startled. Will Sorenson was approaching from the elevator.

"Crap," Beckett muttered under her breath, then winced anew when she saw Castle's reaction. Oops. She hadn't intended for him to hear that.

Grimacing, she hit the Save button on the warrant, and then the button to print it out, before looking up and plastering on a smile. "Hi, Will."

"Hi." Will looked from her to Castle and then back again, his forehead creasing. "Listen... can we talk?" He scowled in Castle's direction again. "In private?"

Beckett pursed her lips and pushed her chair back from the desk to stand up. "Now's not a great time," she said, hoping it sounded apologetic. "We have to get this warrant served before our suspect destroys the evidence."

"Oh." Will nodded understanding. "Okay, well, uh..."

"Later today? I'll call you," Beckett offered, feeling very uncomfortably conscious of Castle's attention. She wasn't looking forward to that conversation with Will, not in the slightest... but she couldn't avoid it for long either.

"Okay. Sure." Sorenson nodded again, and, with a last look at Castle, turned to leave.

"Shut up," Beckett said to Castle, for what felt like the thousandth time. He raised his eyebrows at her.

"I didn't say anything."

The printer on a side table clattered and clacked, spitting out Beckett's warrant and saving her from the need to say anything further. Relieved, she grabbed her coat and purse, whisked the sheets of paper from the printer, and headed for the elevator with Castle on her heels.

* * *

A little while later, Beckett and her team regrouped outside Harrison Tisdale's apartment building. Beckett had the warrant, which she and Castle had gotten Judge Markway to sign; and McNulty filled them in on another piece of the puzzle: the fact that Harrison's business was on the verge of bankruptcy.

"But with his sister's share of the Tisdale fortune, he stands to pay off his debt and then some," Castle mused.

Beckett exchanged a glance with the other detectives. She could see them thinking the same thing she was thinking: it was one thing to let a civilian follow her around to interviews and warrant requests, but this was a potentially dangerous situation, and she needed to keep Castle contained.

"Castle," she said briskly, flashing McNulty and Ryan a quick wink, "if you're going in, you should be armed. My backup's in the glove compartment." She nodded toward her cruiser, parked at the sidewalk with the others.

Castle's face lit up. He yanked the car door open and began to root around in the glove compartment, not noticing that Beckett was pulling out her handcuffs. She nodded to the other cops, who were watching with amusement, and then she bent down and swiftly cuffed Castle to the grab-bar inside the car.

"Hey!" he exclaimed, turning wide startled eyes up to her. Once again Beckett had to hold back a shiver that threatened to overtake her whole body at the nearness of Castle, the focused attention of his bright blue eyes. _Will never makes me feel like this_ , she thought fleetingly before forcing herself back to the situation at hand.

"This time you're staying put," she told Castle, and turned away, ignoring his cry of protest and the chuckles of the other cops.

Esposito, Ryan, and McNulty, as well as an assortment of uniformed officers, accompanied Beckett upstairs to the hallway outside Tisdale's door. But by the time they got inside, Tisdale was gone. His shredder was still warm, so he couldn't have gotten far.

Beckett was about to call out to her detectives to check for other exits when her cell phone rang. Castle's name was displayed on the screen, and as she lifted the phone to her ear, part of her brain was wondering how the hell he had gotten her number.

"He's coming down the fire escape!" Castle's voice shouted in her ear as soon as she accepted the call. Beckett let out a curse, looking around the room and immediately spotting the open window.

"He's out back. Cover the front!" she yelled to the other cops as she stuck her head out the window. Tisdale's head was just barely visible, moving quickly down toward the street. She called "Stop! Police!" but wasn't at all surprised that Tisdale ignored her.

As Beckett was climbing out the window, she saw another moving figure, and she said a few more swear words. What the hell? How had Castle gotten free from her handcuffs? And why was he chasing after their suspect, unarmed?

"Castle, no!" she shouted, scrambling to descend the metal stairs.

She got down to ground level as fast as she could, but by the time she reached the pavement, neither Castle nor Tisdale nor any of the other cops were in sight, and her view of the rest of the alleyway was blocked by a truck. Beckett whispered a few more curses to herself as she drew her gun and began to make her way slowly down the length of the vehicle.

All of a sudden she found herself in a standoff, her heart in her throat as Tisdale stood holding Castle hostage with a gun to his head. Beckett called on all of her training and practice in tense situations to keep calm, to ignore the pounding of her pulse and stay focused on the suspect.

Castle, of course, had no such training and no such restraint.

"Why didn't you just ask your father for the money?"

"Castle, you are not helping!" she exclaimed, shifting her grip on her gun. She could see the anger and desperation in Harrison Tisdale's eyes, and she didn't like the look of it.

But Castle gave her a hand gesture and a nod to indicate that he wanted her to believe he had a plan. She had no confidence in his planning, none at all - but whatever he had in mind, maybe it would at least buy them some time.

Tisdale's eyes were darting around the small space, searching for a way out, but as Castle put together the last pieces of the puzzle, the killer became more agitated. Beckett knew it was time for her to intervene.

"Harrison, let him go," she ordered, stepping out from behind the cover of the truck, advancing on them with her gun held steady on Tisdale's face. "It's over."

"It's not over!" he yelled. "It's not over! Drop the gun or I swear to god I'll-"

As soon as Tisdale moved his gun from Castle's face to point at Beckett, several things happened all at once. Castle elbowed Tisdale in the face; Beckett took another quick step forward; and Will Sorenson came barreling around the corner, gun drawn, shouting, "FBI! Freeze!"

"Seriously?" yelled Castle, as Tisdale, falling, lost hold of his gun, sending it clattering to the ground. "I almost had that! I swear!"

Tisdale lunged for the gun, but Beckett was faster, scooping it up with her free hand and in the same motion placing her foot on Tisdale's back, pressing him down onto the pavement.

"Tell me you saw that!" Castle pleaded. "I would've caught that gun if your stupid Federal Agent Man hadn't distracted me."

"What the hell are you doing here, anyway?" Beckett demanded, twisting around to look at Sorenson, even as she was kneeling on Tisdale's back and reaching to retrieve her handcuffs from Castle.

"I... I just thought you might need some backup," Will said, scowling. He holstered his gun and glared at all three of them. "I guess you have this all under control."

"Yeah," Beckett agreed, turning away from him to focus on cuffing her suspect, her jaw clenched so hard it almost hurt. "Looks like I do."

* * *

 _Thanks for reading! The final chapter will be posted this weekend._


	6. Chapter 6

"Well done, Detective," said Captain Montgomery as Beckett emerged from the interrogation room, where she had just finished overseeing Harrison Tisdale writing out his confession. "You were right to reopen this case."

"Thank you, sir." Beckett hesitated, wondering whether she should say something about Castle and his involvement in the case.

Would she have kept pushing for the truth after they had arrested Kyle Cabot, if not for Castle's insistence? She bit her lower lip, dithering, but it was too late anyway; Montgomery had gone back into his office, leaving Beckett to hide her consternation behind a bright smile for Ryan and Esposito.

"Nice work, Beckett," Espo said.

"Yeah, good catch," Ryan agreed.

She nodded and fist-bumped both of them. "Thanks, guys. See you tomorrow."

Castle was standing beside her desk when she came through the bullpen with the Tisdale file folder. They exchanged awkward smiles.

"Well," Beckett said, putting the file down on her desk, "uh, I guess this is it."

"Yep, looks that way," Castle agreed. "Time for you and Federal Agent Boy to go to dinner, debrief each other." His eyes slid sideways, toward Sorenson, whom Beckett could see talking to another detective at the other end of the bullpen.

Beckett's mouth twisted in distaste. "Yeah, that's not going to happen," she muttered under her breath.

"Sorry?" Castle asked, his eyebrows raised inquisitively.

"Nothing." She gave him a businesslike nod. "It was nice to meet you, Castle."

She couldn't bring herself to offer Castle another handshake, so she simply nodded again and turned away, feeling his eyes follow her the whole way across the room. Her heels tapped sharply on the floor as she strode over to where Sorenson was standing.

"Will," she said quietly, "we need to talk."

"Yeah."

Sorenson followed her into an unoccupied interview room, where she closed the door and took a deep breath, steeling herself, before she turned to face him again.

But Will spoke before she could get out the careful sentence she was constructing in her head. "Listen, I'm sorry," he said earnestly, holding out a hand in supplication. "For almost botching your bust today, and... and I'm sorry for everything else too, Kate. I should have told you the job was in Boston. I should have had that conversation with you as soon as I first heard about it."

"Yeah, you should have," she agreed. "Look, Will, obviously this isn't going to work out, so-"

"What? No," he protested in surprise. "I didn't - Kate, we can talk this out. We can fix it."

"I don't think so," she said slowly. She hated the distressed look on his face, and the knowledge that she had caused it... but she wasn't backing down. Somewhere during all the madness of the day, she had come to this decision, and she knew it was the right one. "I don't think so," she repeated. "I'm sorry."

"It's because of him, isn't it?" Will snapped, scowling. " _Castle_. You're dumping me for him."

"No," she said firmly. "God, Will, you just don't get it. I'm dumping you because you don't respect me - as a person, or as a cop. You've shown that a dozen times over during the past few days."

"I respect you," he insisted. "Do you think he does? Kate, he's nothing but a player. He's played you to a T. He'll just use you and then toss you aside. You think he can compare to me?"

"I told you, this isn't about Castle," Beckett said, hearing her voice rising as the frustration built up. "You don't listen to me, Will. This is about _you_ and how you've been treating me. Keeping important information from me, making decisions about our relationship and my _life_ without even consulting me..." She paused, took a breath, and added heatedly, "But since you brought it up, at least Castle took me seriously on this case. _He_ didn't question my professional judgment or dismiss my concerns about the evidence."

"Oh, please," Will scoffed. "He's just trying to get in your pants, Kate. You should have screwed him when I suggested it the other day. Then you and I could be working on this."

"There's nothing to work on!" She struggled to get her volume under control. "It's over, Will."

"Okay. Fine. But don't think you can come crawling back to me when you realize what a big mistake you made," he sneered.

Beckett let out a frustrated growl and yanked the door open. "Not gonna happen. Have fun in Boston."

She stalked down the hallway and through the door into the stairwell, stopping after the heavy door clanged shut behind her. She leaned against the chilly concrete wall and put both hands over her face, struggling to get her emotions under control. Her pulse was pounding in her ears, her breath coming fast and hard. Her face felt hot and tight with anger.

The urge to go back to the conference room and yell at Will some more was overpowering, but she pushed it down. What was the point? Lanie was right: she should have broken up with Will a long time ago.

She was still grappling with the seething turmoil of emotions when the stairway door opened again, and Castle poked his head in. "Beckett? Everything okay?"

"Wh..." She stared at him, astonished and a little uneasy. "What are you still doing here? I thought you left."

"Oh, yeah..." He waved a hand vaguely as he slipped into the stairwell and let the door close again. "Just saying goodbye to everyone, you know."

Beckett's eyebrows drew together as she looked at Castle for a long moment, her mind whirling.

Then she found herself surging forward, reaching for him, everything else be damned. She grabbed Castle's head and pulled him down to her, fusing their mouths together.

He froze for an instant, surprised, but then he came alive in her arms. He pushed her back against the cold wall and pressed his body against hers, hot and hard, his hands firm on her hips. Their tongues found each other immediately and their kiss was searing, dizzying, almost frantic. Beckett heard herself moan urgently into Castle's mouth as she dug her fingers into his hair and tugged him even closer.

But eventually he wrenched his lips away, sliding sideways to press them tantalizingly against the edge of her jaw before speaking into her ear. His voice was low and husky, sending jolts of excitement through her.

"Don't get me wrong, Detective," he murmured, "I'm perfectly happy to be your rebound guy, but just to be clear, you really did break up with him this time, right?"

"Yeah," she grumbled, trying to pull his face back up to hers. "I really did. And I don't want to talk about it."

Castle succumbed to the tug of her fingers, reclaiming her mouth for another hard, hot kiss that made her knees go weak. But too soon he was pulling away again, and talking again.

"Beckett." She shivered at the way he said her name, raw with desire. But his next words weren't what she expected. "I have a confession to make."

Beckett frowned, confused. "What?" she asked, struggling to think through the haze of lust and frustration.

"I know about the list," Castle said.

She blinked, staring at him as he pulled back just far enough to meet her eyes. "What do you mean? What list?"

"You know." He smirked slightly, his eyebrows wiggling. "The celebrity freebie list. Mister Boring told me about it."

"Oh my god." Beckett pushed him away and covered her face with her hands again, groaning, thoroughly mortified. Her cheeks were on fire. "Why on earth would he do that?"

"I don't know." Castle sounded amused. "We were in the observation room, watching you make Tisdale write his confession - that was awesome, by the way, you were amazing in there-"

" _Castle_."

"-and out of the blue he just said, 'I'm surprised you haven't slept with her yet,'" he went on, "and I was like, 'uhh, I thought she was with you,' and he goes, 'well I don't know why that would stop you - she's hot, you clearly like her, and you're on her freebie five list.'" He gave a short huff. "Is that guy for real?"

"Unfortunately," Beckett sighed from behind her hands. "I can't believe he told you that."

"I know," he chuckled. "What a dork. Hey, come on, don't be embarrassed."

"That's easy for you to say." She uncovered her face, but still couldn't bring herself to look at him. She felt almost nauseated by the mixture of emotions churning through her. She wished she had a hole to crawl into and hide. Preferably forever.

"Beckett. Hey." Castle touched her shoulder lightly, drawing her attention back onto him. Reluctantly, she dragged her eyes back up to his again. He was grinning, his face alight with mischievous pleasure.

"So who else is on your celebrity sex list?" he asked with evident relish. She groaned again.

"Forget it, Castle. That's like fifth-date territory."

"Fair enough," he shrugged. "I'll get it out of you eventually."

"What?" She stared at him, bemused. That couldn't possibly mean what it sounded like. Could it?

Castle moved closer, slipping an arm around her waist. She had half a heartbeat to wonder whether she should punch him for the presumption, but then he was kissing her again and all thought flew out of her head.

She couldn't resist kissing him back, her hands in his hair, his own hands hot on her back, scorching her skin through the fabric of her shirt. But then her shoulders hit the concrete wall again and she came back to her senses, at least enough to push Castle away, gasping, "Wait - wait."

He pulled back slightly, loosening his hold on her. "Look, I get it," he said, a bit breathless, his deep blue eyes suddenly serious. "You just got out of a relationship like five minutes ago. You don't want to do anything rash."

"Maybe I do," she mused, fighting to clear her head. It was nearly impossible to think past the frustrated lust that had been building ever since she met Castle a few days ago. But wasn't that what Lanie had said she should do - take some risks? "Maybe I want to be another one of your conquests," she said, meeting Castle's eyes with renewed confidence, pulling him closer again.

"I'd rather be one of yours," he answered huskily. "I think it's gonna be great."

"You have no idea," she whispered just before his mouth came crashing down on hers again.

* * *

 _Thanks for reading! I hope you enjoyed the story. Have a lovely weekend, everyone._


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